<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .one {
          color: red;
      }
      .two {
          font-size: 48px;
      }
  </style>
  </head>
  <body>
    <div id="app">
      <div :class="{one:oa,two:ta}"  style="width: 100px;height: 100px; border: 1px solid red ;">
        abcd
      </div>
    </div>
  </body>
</html>
<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script>
    const app = Vue.createApp({        
    data() { //  定义对象的属性
      return {
        msg: "hello",
        oa: true,
        ta: true
      };
    },
  });
  app.mount("#app");
</script>
